Roller table roll, particularly for conveying furnace-heated metallic strip material

ABSTRACT

The invention relates to a roller table roll used, in particular, for conveying furnace-heated metallic strip material, cast billets made of steel and the like. The roller table roll comprises a roll shaft ( 4 ) and a roll casing ( 1 ) that is mounted on the roll shaft ( 4 ) at least at the roll ends ( 2; 3 ). The aim of the invention is to prevent damages caused by electric currents and by sparking on the product surface. To this end, the roll casing ( 1 ) is mounted on the roll shaft ( 4 ) while being electrically and/or thermally insulated at least at the roll ends ( 2; 3 ).

[0001] The invention relates to a roller-conveyor roller, especially forthe transport of furnace-heated metallic strip material, continuouscastings of steel or the like, with a roller shaft and a roller shell[casing] journaled on the roller shaft at least at the roller ends.

[0002] Because of a general difference in the electrical potentialsbetween a metallic product and a roller-conveyor roll, electricalcurrents and spark formation can result in surface defects in themanufactured material.

[0003] It is known (DE 24 26 135 C2) to provide a roller conveyor rollfor the transport of rolled products [rolling mill products] which canresist impact with the rolled product. It has not been noted thereinthat such roller conveyor rolls also contribute to electrical currentsand spark formation which can degrade the rolled product.

[0004] The invention has therefore as its object to suppress suchelectrical currents and spark formation so that the mentioned damage nolonger can arise. The object set forth is achieved according to theinvention in that the roller shell or casing is electrically and/orthermally insulated at the respective roller ends, at least, where it isjournaled on the roller shaft. Such a roller conveyor roll is suitablefor roller conveyors or roller conveyor segments in regions of inductiveheating and induced electrical fields as well as wherever generaldifferences in electrical potentials between a rolled product orcontinuously-cast product and a roller conveyor roll can arise andwherever electrical currents and spark formation can contribute tosurface defects. Advantageously, such a roller-conveyor roll can also beused to largely suppress the heat transfer by conduction between theroller casing or shell heated by a product and the roller shaft orroller axle which as a rule is cooled.

[0005] A further feature of the invention is that between the rollercasing at the roller ends and the roller shaft, individual insulatingbodies are distributed around the respective peripheries or a one-pieceannular insulating body is provided. The insulating bodies can thusserve to center the roller casing on the roller shaft and/or for torquetransmission there between.

[0006] In a feature of the invention the individual insulating bodiesdistributed around the periphery are comprised of profile rods. Theprofile can be round rods, flat or rectangular cross sections or can becomposed of other cross sectional shapes. The material for such profiledbars can be of ceramic or other insulating materials of correspondingstrength.

[0007] A further advantage arises when the profile bars are axiallysecured with respect to the roller shaft and the roller casing togetherwith bearing rings.

[0008] To restrict axial shifting it is for example advantageous for theaxial securing to be achieved with sheet metal rings welded onto theends of the bearing.

[0009] While the roller casing and the roller shaft are basicallyseparate from one another and are connected together exclusively bymeans of the insulated bodies, by means of the axial retainers, a loosebearing and a fixed bearing can be formed between the roller casing andthe roller shaft. As a result, thermal stresses can be compensated andthermal expansion and contraction can be accommodated.

[0010] Basically a further advantage is achieved in that the insulatingbodies can center the roller shell on the roller shaft andsimultaneously form a torque transmitting medium. In this manner acompact unit which is advantageous for any requisite force transmissionin a roller conveyor roll is obtained.

[0011] In an alternative embodiment, the roller shell or casing issubdivided into roller shell segments arranged in the roller shaft andmounted on the roller shaft by insulated bodies which serve to centerthem on the roller shaft and for torque transmission. The insulatingbodies are distributed around the periphery of the roller shaft. In thismanner the roller shell or casing segments are separated from the rollershaft and are exclusively connected through the described insulatingbodies.

[0012] According to a further alternative, the insulating body isconfigured as a conical bearing whose cone shaped inner ring and/orwhose cone shaped outer ring and/or their conical rollers respectivelyform insulating bodies. Because of the short roller casing segments thelongitudinal expansion and contraction and the expansion and contractionresulting from heating in the axial direction has play which isnegligible so that no arrangement of loose bearing and fixed bearingunits are required. In this manner electrical currents in the axialdirection are especially suppressed.

[0013] A further feature of the invention is that any increased play inthe mutual fitting of the insulating bodies and their retaining portionsresulting from heating of the roller casing can be compensated by thefact that the conically shaped inner ring is axially shiftable and isadjustable against a spring force on the roller shaft.

[0014] The inclination of the cone [cone angle] is then so selected thatbecause of the longitudinal expansion of the roller casing or shell theouter cone assumes a different position upon the inner cone and therebylargely compensates for the expansion of the diameter.

[0015] In a practical embodiment the conically shaped inner ring isbiased on the roller shaft by means of dished-disk springs which can beseated against a step or shoulder on the stuff and against the hollowconical outer ring which is fixedly connected to the roll casing orshell and which is shiftable axially with respect to the roller shaft.The play is continuously eliminated by the spring force.

[0016] Another configuration provides that a roller shell segment isjournaled at the respective roller ends in respective conical bearingsand generally centrally by means of insulating bodies distributed overthe periphery.

[0017] In the drawing embodiments of the invention are shown and aredescribed in greater detail in the following.

[0018] The drawing shows:

[0019]FIG. 1 an axial longitudinal section through a first embodiment ofthe roller conveyor roll,

[0020]FIG. 2 an axial longitudinal section through a second embodimentof a roller-conveyor roll with roller casing or shell segments,

[0021]FIG. 2a the associated side view,

[0022]FIG. 3 an axial longitudinal section through a third embodiment ofthe roller conveyor roll,

[0023]FIG. 3a the associated side view, and

[0024]FIG. 4 an axial longitudinal section through a fourth embodimentof the roller conveyor roll.

[0025] The roller conveyor rolls serve for example for transport ofstrip material which passes out of a treatment furnace or for thetransport of continuous-casting strands, for example. The basicstructure encompasses a roller shell or casing 1. The latter isjournaled at least at the roll ends 2 and 3 in respective electricaland/or thermal insulators on the roller shaft 4 (FIGS. 1 and la as afirst embodiment).

[0026] The insulation is comprised of individual insulating bodiesdistributed around the periphery of the roller shaft 4 between theroller shell or casing 1 and the roller shaft 4 at the roll ends 2 and 3(FIG. 1, 1A, FIG. 2, 2A and FIG. 3, 3A). Alternatively, a one-pieceannular insulating body 6 (FIG. 4) can be provided.

[0027] The individual insulating bodies 5 distributed around theperiphery are comprised of profile rods 7 which have a round, flat,rectangular or polygonal cross section. The profile bars 2 are comprisedof ceramic or some other material having an insulating effect.

[0028] The roller shaft 4 is equipped with bearing stubs 8 and 9 and iscooled by means of a cooling medium which flows through a core channel10. The profile bars 7 are secured together with bearing rings 11 and 12on shaft steps 13. The axial retaining is effected by sheet metal rings17 welded onto the ends 14 and 15 and which are respectively appliedtogether with the bearing 16 formed by the profiled rods 7. Thesebearings 16 can be formed as a loose bearing 16 a and a fixed bearing 16b to allow thermal expansion. The insulating bodies 5 center the rollshell 1 on the roller shaft 4 and form simultaneously by form lockingand/or force locking a torque transmitting means.

[0029] In a second embodiment (FIGS. 2, 2A) the roller shell or casing 1is subdivided into a plurality of spaced apart roller shell segments 1a, 1 b, 1 c, 1 d, etc. arranged upon the roller shaft 4 and which arecentered on the roller shaft 4 with respect to the insulating bodies 5and transfer the drive torque.

[0030] According to a third embodiment (FIGS. 3 and 3A) the insulatingbody 5 is configured as a conical bearing 18 of which either the conicalinner ring 18 a or the conical outer ring 18 b and or the conicalrollers 18 c respectively form the insulating bodies 5.

[0031] In the fourth embodiment (FIG. 4) the conically shaped inner ring18 a is axially shiftable and is adjustable against the spring forceupon the roller shaft 4. The conical inner ring 18 a is braced on theroller shaft 4 axially by means of dish-disk springs 19 which are seatedagainst a shaft step 20. The ring 18 a is shiftable relative to thehollow conical outer ring 18 b fixedly connected with the roll shell orcasing 1. The torque in this configuration is transferred by frictionalconnection to the conical outer ring 18 b. The insulating material isthe ceramic from which the conical outer ring is composed.

[0032] Instead of ceramic, glass fiber textiles can be used in acorresponding thickness or layering.

[0033] A roller shell or casing segment 1 a, 1 b, etc. can at each ofthe roller ends 2 and/or 3 be journaled in the conical bearing 18somewhat centrally by means of insulating bodies 5 distributed over theperiphery.

[0034] To limit creep currents over the surface of the insulating body 5a dryed ambient atmosphere is applied. Such an atmosphere can beobtained for example in the region of a treatment furnace.

[0035] Reference List

[0036]1 Roller shell or casing

[0037] la Roller casing segment

[0038]1 b Roller casing segment

[0039]1 c Roller casing segment

[0040]1 d Roller casing segment

[0041]2 Roller end

[0042]3 Roller end

[0043]4 Roller shaft

[0044]5 Individual insulating Body

[0045]6 One piece insulating body

[0046]7 Profiled bar

[0047]8 Bearing step

[0048]9 Bearing step

[0049]10 Core passage

[0050]11 Bearing ring

[0051]12 Bearing ring

[0052]13 Shaft step

[0053]14 End

[0054]15 End

[0055]16 Bearing formed from profiled bars

[0056]16 a Loose bearing

[0057]16 b Fixed bearing

[0058]17 Shell metal ring

[0059]18 Conical bearing

[0060]18 a Inner cone-shaped ring

[0061]18 b Outer cone-shaped ring

[0062]18 c Conical rollers

[0063]19 Dished disk spring

[0064]20 Shaft step

1. A roller conveyor roll, especially for the transport offurnace-heated metallic strip, continuously cast stands of steel or thelike with a roller shaft and a roller shell or casing journaled at leastat the roller ends on the roller shaft, characterized in that the rollershell (1) is journaled on the roller shaft (4) at least at the rollerends (2, 3) respectively with electrical and/or thermal insulation. 2.The roller conveyor roll according to claim 1 characterized in thatbetween the roller casing or shell (1) at the roller ends (2, 3) and theroller shaft (4), respective individual insulating bodies (5)distributed over the periphery or annular insulating body (6) areprovided.
 3. The roller conveyor roll according to claim 2 characterizedin that individual insulating bodies (5) or profiled rods (7) aredistributed over the periphery.
 4. The roller conveyor roll according toone of claims 1 to 3 characterized in that the profiled bars (7)together with bearing rings (11, 12) are axially secured relative to theroller shaft (4) and the roller shell (1).
 5. The roller conveyor rollaccording to claim 4 characterized in that the axial retention iscomprised of a sheet metal ring (17) welded on the ends (14, 15) of thebearing (16).
 6. The roller conveyor roll according to one of claims 4or 5 characterized in that by means of the axial retention, a loosebearing (16 a) and a fixed bearing (16 b) are formed between the rollershell (1) and the roller shaft (4).
 7. The roller conveyor rollaccording to one of the claims 1 to 6 characterized in that theinsulating body (5) centers the roller shell or casing (1) on the rollershaft (4) and simultaneously forms the torque transmitting means.
 8. Theroller conveyor roll according to one of the claims 1 to 7 characterizedin that the roller shell (1) is subdivided into a plurality of spacedapart roller shell segments (1 a, 1 b, 1 c, 1 d) arranged on the rollershaft 4 and centered with a plurality of insulating bodies (5)distributed around the periphery respectively and serving as drivetorque transferring members.
 9. The roller conveyor roll according toclaim 1 characterized in that the insulating body (5) is configured as aconical bearing (18) whose conical inner ring (18 a) and/or whoseconical outer ring (18 b) and/or whose conical rollers (18 c) formrespective insulating bodies (5).
 10. The roller conveyor roll accordingto claim 9 characterized in that the conical inner ring (18 a) isaxially shiftable and adjustable under spring force on the roller shaft(4).
 11. The roller conveyor roll according to claim 10 characterized inthat the conical inner ring (18 a) is axially shiftable on the rollershaft (4) by means of dished disk springs (19) which are braced againsta shaft step (20) relative to the hollow conical outer ring 18 b fixedwith the roller shell (1).
 12. The roller conveyor roll according to oneof claims 8 to 11 characterized in that a roller shell segment (1 a, 1b, etc.) is respectively journaled at a roller end (2, 3) in a conicalbearing (18) and substantially midway by means of insulating bodies (5)distributed around the periphery.